A non-contact three-dimensional (3D) geometry measuring instrument that performs 3D measuring of an object to be measured by using a plurality of measured images is known.
The non-contact 3D geometry measuring instrument generates an intermediate image to measure a geometry of the object to be measured by using the measured images. Since various types of noise are included in the measured images, similar noise is also included in the intermediate image.
Non-Patent Document, S. Montresor, et al., “Optics Express,” Vol. 24, Issue 13, pp. 14322-14343, 2016, discloses a technique that removes noise of an intermediate image using various filters. However, in the technique disclosed in the above-mentioned Document, there was a problem that an area where noise is not sufficiently removed remained in the intermediate image.